Ship construction



Feb. 19, 1952 J. VASTA SHIP CONSTRUCTION 2 SHEETS-SHEET 1 Filed June 26, 1946 INVENTOIL M ATTORNEY:

Feb. 19, 1952 .1. VASTA 2,585,980

SHIP CONSTRUCTION Filed June 26, 1946 2 SHEETS-SHEET 2 INVENTOR Jomv 1495 TA I la Patented Feb. 19, 1952 UNITED STATES PATENT OFFICE (Granted under the act of March 3, 1883, as amended April 30, 1928; 3'70 0. G. 757) 2 Claims.

The invention described herein, if patented, may be manufactured and used by or for the Government of the United States for governmental purpcses without the payment to me of any royalty thereon or therefor.

The present invention relates to ship construction having corrugated or fluted bulkhead plating generally similar to that in U. S. Patent 2,218,688, issued October 22, 1940, to J. W. Stewart.

It has been found in most of the ships constructed in this manner, with longitudinal or transverse corrugated bulkheads welded alternately to the flanges and web of an I-beam at their intersection, that discontinuity of strength occurs at the flange welds, resulting in great concentration of strains in the flange welds, particularl the lower portion thereof. Furthermore, in the case where longitudinal corrugated bulkheads are welded to' the flanges of the I-beam, this stress concentration is great enough to break the weld at the lower junction of the corrugated longitudinal bulkhead with the flange.

I have discovered by full size ship structural tests that the application of a certain type of bracketing at the point of greatest stress concentration can relieve and redistribute the strain such that breakage of welds at this point is overcome, and the danger thereof in rough seas under conditions of highest strain minimized.

The present invention is concerned primarily with a bracketing method whereby ships already constructed of corrugated bulkheads may be readily repaired so as to relieve the stress concentrations. This type of bracketing may also be applied to other corrugated construction as additional safety factor. For example, the uppermost sloping surfaces of a corrugation are also severely stressed and additional bracketing at this point is often desirable. This type of bracketing also may be applied to construction where the corrugations of transverse bulkheads are welded to flanges, a case wherestress concentrations at the lower part of the flange are great but not usually great enough to break the weld. It will be understood, however, that the most usual application is at the junction of a corrugated longitudinal bulkhead with an I-beam flange at the intersection with a transverse bulkhead and it is accordingly the primary object of the present invention to provide bracketing to relieve stress at this juncture.

Figure 1 is a perspective view, partly in section, of a vertical beam welded to radiating bulkheads to which my reinforcing means have been applied.

Figure 2 is a section on the line 2-2 of Figure 1.

Figure 3 is a section on the line 3-3 of Figure 2.

Referring to the drawing Figure 1, a typical corrugated type intersection of bulkheads at the lower part of an I-beam is shown wherein [0 indicates the'web of the I-beam having T-iron flanges II welded thereto at [2, the web It! and and flanges ll welded thereto comprising a fabricated I-beam. Transverse bulkhead I3 having a deep corrugation or flute I4 is welded to each side of the web so that transverse stresses are evenly and continuously transferred through the intersection. Longitudinal bulkhead l5 having a deep corrugation I6 is welded to the face of each flange H of the I-beam in a continuous weld I1. It is along this weld II that maximum strains occur and parting of the weld takes place beginning at the mid point of the sloping faces of the corrugation of the bulkhead where the stress concentration is severest.

I have found that strain in the weld I1 is reduced if bracket I8 is attached by welding above midway of a sloping face. of the slanting plane portion [9 of the corrugation or flute I6, with the vertical edge attached by welding to and midway of the flange of the I-beam; and if a second similar plate bracket I8 is welded directly beneath the first bracket with the center of the portion H! in the plane of the web I0 of the I-beam, the strain in the weld at this point is relieved to a maximum as shown by strain gage study and there is no danger of the weld subsequently parting.

I have found, further, that the strain in the weld is also adequately relieved by welding a pair of plate brackets 20 on opposite sides of the web I0 and welding abutting edges of said brackets 26 to the inner face of flange II on their respective sides of the web, with both brackets 20 lying in the slanting plane of the bend IQ of the corrugation 16.

The brackets l8 serve to transfer bulkhead stresses axially to the flange II and thence to web III, while the brackets 20 transfer stresses through the flange to the web of the I-beam. Either or both types of brackets may be used as shown but the strain gage study indicates that the brackets I8 are most eflicient.

It will be understood that additional brackets may be placed at other points if desired, but only bracketing as herein described at the corrugations is completely satisfactory to overcome parting of the welds and relieving strain concentration therein.

While I have shown welded plate brackets as a preferred form it will be understood that various modifications of the shape, construction or type of bracket as well as the method of fastening the same may be used so long as they are applied to relieve stress at the junction of the sloping plane of the bulkhead corrugation with the I-beam flange by placing them either parallel to the web of the I-beam or parallel to the sloping plane of the corrugation.

I claim:

1. A bulkhead construction for a ship, a vertical bulkhead extending longitudinally of a ship, said bulkhead having horizontal extending corrugations each corrugation having a vertical portion joining a pair of converging portions, a vertical I-beam intersecting the bulkhead and Welded thereto with the flanges of the beam abutting opposite portions of said bulkhead, a pair of vertical brackets one disposed on each opposite side of one of said converging portions approximately in the plane of the web of the beam and approximately at the mid-point of said one converging portion and welded to said one converging portion and to the flange of said beam whereby the stresses are distributed from the bulkhead to the beam.

2. A bulkhead construction for a ship, including a plurality of vertical bulkheads each exhead to the beam.

tending longitudinally of a ship, said bulkheads having horizontally extending corrugations each corrugation having a vertical portion joining a pair of converging portions, a plurality of vertical I-bearns intersecting the bulkheads and welded thereto with the flanges of the beam abutting opposite portions of each of said bulkheads, the improvement which comprises a pair of vertical brackets one disposed on each of the opposite sides of one of said converging portions approximately in the plane of the web of the beam and approximately at the midpoint of said one converging portion and welded to said one converging portion and to the flange of said beam whereby the stresses are distributed from the bulk- JOHN VASTA.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,294,962 Smith et al Feb. 18, 1919 1,769,831 Gram July 1, 1930 2,218,688 Stewart Oct. 22, 1940 

